1. Field of the Invention
A flush valve control apparatus to selectively control the volume of water dispersed from a water closet flush tank.
2. Description of the Prior Art
Sanitary water closets have for years been constructed with a water storage tank secured to the back side of the toilet bowl. The tank is connected to the domestic water supply. An automatic fill valve mechanism in the tank includes a float-operated valve for filling of the storage tank to a selected level. Normally, tanks are presently constructed to hold between six and eight gallons of water. The bottom of the storage tank is connected to the toilet bowl with a normally closed ball valve structure. A flush handle on the storage tank is coupled through a linkage mechanism to the ball valve. Opening of the valve discharges the stored water from the tank for flushing of the toilet bowl. For many years, a simple float ball valve on a suitable guide stem was used. More recently, a flapper-type ball valve is also used, wherein the ball valve is secured by a rubber hinge directly to the overflow tube. Actuating of the flush handle results in the lifting and pivoting of the ball valve about the rubber hinge.
Conventional flush tanks now in general use discharge the entire amount of water stored in the tank upon each flushing operation even though only a fraction of that quantity of water may be required for flushing the waste material. This results in unnecessary water consumption increased water costs and presents special problems where the water is flushed into a cesspool or septic tank. In many places there is a critical shortage of water. This waste contributes significantly to the shortage. In addition, many municipal waste disposal systems are already overburdened with the increasing quantities of sewerage water that flows through the sewer systems and treatment plants.
It has long been recognized that substantial water saving can be achieved by the provision of a variable flushing control for varying the quantity of water utilized in flushing in accordance with the quantity and character of the waste material to be flushed. Toward this end, various water saving flush tanks and variable flushing control devices have been proposed in the past.
One type of flush tank includes a partitioned tank, separate water discharging devices and duplication of plumbing for discharging water from one or both parts of the partitioned tank. In another type, the discharge of water from the tank is controlled by two columns in end-to-end relationship with provision for lifting the upper column for a partial f-Lush and both columns for a full flush.
Other types of variable flushing control devices have been proposed which rely on the venting of air from the conventional hollow ball valve to effect a partial flush. For example, in the variable flushing control device described in U.S. Pat. No. 2,741,776, a tube supporting a ball-type discharge valve has a positively actuated valve at the upper end thereof to partially exhaust air from an air chamber within the bail valve when the ball valve is lifted to bring the valve into contact with an actuating bar. The partial evacuation of the air from the ball valve permits gradual reseating of the ball valve upon release thereof. A number of other systems using the venting principle have been devised, but in general, such prior art employ complicated and expensive structures and are not adapted for use in conventional flush tanks.
U.S. Pat. No. 4,945,580 teaches a vented buoyant outlet closure allowing the flapper to prematurely terminate the flushing cycle. The venting is controlled by turning the externally mounted operating handle in one direction. When the operating handle is turned in the opposite direction, essentially all the water is discharged from the tank effecting a full flush cycle.
U.S. Pat. No. 3,546,715 shows an adjustable toilet tank flush valve in which the discharge of water from the tank is reduced in accordance with the setting of an adjustable vent valve. A slidable control member is incorporated with the handle to override the reduced discharge and permit a full tank discharge.
U.S. Pat. No. 4,000,526 teaches a flush valve assembly for a partial flushing operation including a floating flapper valve device for sealing the drain valve seat. The floating flapper valve device includes an air trapping float chamber and an inlet mounted in fluid communication with the chamber for trapping air in the chamber to delay the closing of the flapper device. A vent mounted in fluid communication with the chamber enables at least some of the trapped air to be released from the chamber enabling the flapper device to close prematurely thereby causing a partial flush operation to occur. A trip lever assembly controls the operation of the floating flapper valve device for full flush operations and to control the vent for a partial flushing operation.
U.S. Pat. No. 4,175,296 teaches a toilet flush tank having an attachment including an air passage for venting the air chamber and a water level responsive valve normally closing the air passage when the water within the tank is above a predetermined height and for venting the air chamber when the water within the tank is a predetermined height.
U.S. Pat. No. 4,225,987 shows a tank flush mechanism in which the trapped air in the flush discharge valve is vented to terminate the flush when the water level in the tank drops to a predetermined level. To provide a large volume flush, the flush handle is manipulated thereby allowing the flushing action to continue.
U.S. Pat. No. 4,593,419 discloses a buoyancy control unit for the flapper-type ball valve of a water closet flushing unit including a flexible air release metering tube connected to the outer peripheral portion of the flapper valve ball and extended upwardly from the stored water level. An adjustable meter valve is secured about the tube to adjustably collapse the tube for metering flow of air. A simple strap hanger has an offset apertured support tab through which the tube passes and on which the meter valve rests. The opposite strap end is bent and hooked over the edge of the tank.
U.S. Pat. No. 4,115,880 shows a control system for a toilet valve including an automatically controlled vent valve for controlling the venting of the flush valve to provide a long flush or a short flush controlled by a combination of the toilet flush handle and a float controlled latch within the tank.
Many of these prior art devices disclose various fittings for connecting the air conduit to the flapper. Unfortunately these air conduits represent one of the most trouble prone elements including entanglement with other structures in the tank, blockage due to the presence of water droplets, interference with the travel and function of the flapper valve, and limited life span due to physical wear and chemical degradation. Conduits of sufficient wall thickness to provide adequate life spans tend to be more rigid and thus may interfere with the proper function of the flapper. Conduits of thinner wall thickness are typically less rigid but are more susceptible to kinking and entanglement resulting from water currents present in the tank during the flush cycle. Reduced wall thickness also tends to reduce resistance to physical wear and chemical degradation. Therefore if a device is to function properly, the design of the air conduit should strike a balance between wall thickness and flexibility.
The prior art typically describes a slender, flexible tube with little slack between the control structure and the flapper. In nearly every example this tube takes the shape of a two-dimensional, shallow, "S" curve terminating perpendicularly to the plane of the flapper.
Such a configuration would appear to be desirable as the substantially vertical orientation encourages the drainage of water droplets. Further, by limiting the amount of slack between the control structure and the flapper, the tube is likely to be pulled into contact with other structures by water currents present in the tank.
When the flapper is drawn off the seat to initiate the flush cycle, the air conduit must bend to accommodate the axial movement of the flapper. It follows that the shorter the length of hose over which this bending may occur, the greater the resistance to said bending will be for a given material and wall thickness. Because the solutions of the prior art keep conduit length to a minimum, it is likely they must rely on thin wall sections in order to provide the flexibility necessary to avoid interfering with the operation of the flapper.
Since the lower end of the conduit terminates in a generally perpendicular orientation to the plane of the flapper, the conduit remains relatively distant from the axis of rotation of the flapper. The distance between the conduit and the flapper's axis of rotation combine with compressive or tensile stress in the conduit to create a moment about the axis of rotation which may act in opposition to the movement of the flapper about said axis.
Because the conduit attaches perpendicularly to the flapper, bending stresses in the conduit will have a greater tendency to create moment at the fitting. The effect of such moment is to pry the fitting off or through the surface of the flapper. Compensating for these problems by the use of an extremely flexible conduit generally produces unacceptable results. The lack of rigidity in such a conduit results in little or no resistance to lateral forces applied to the conduit by water currents. Because of this, the conduit is more susceptible to kinking and entanglement with other structures in the tank during the flush cycle.